Piemontite was first described from the Prabornaz mine, Italy in 1758 by Cronstedt as "röd Magnesia", and again as “Manganèse rouge.” by Chevalier Napione in 1790. He also provided a chemical analysis. On the basis of Napione's chemical data Haüy designated the substance as “Manganèse oxidé violet silicifère” in 1801. Cordier (1803) did a new analysis and acknowledged the similarities between piemontite and epidot and named the mineral “Èpidote manganésifere.” A name that was used both by German and English speaking scientists( Manganepidot and manganesian epidote respectively) . Also Haüy (1822) adopted the name “Èpidote manganésifere.” in his grand work Traité de Mineralogie. Werner (1817) chose the name "Piemontischer Braunstein", which was shortened to piedmontite in 1853 by Kenngott, using the English name for the region. Today the Italian spelling is used; piemontite

"Piemontite" has two different uses: Piemontite (sensu stricto) is the mineral species described here, but more commonly "piemontite" refers incorrectly to deep red colored, Mn3+-bearing epidotes that are really varieties of the species epidote, and not strictly speaking piemontite. "Piemontites" rarely contain more than 40% of the piemontite molecule, so many "piemontites" in collections (and pictured here in Mindat) are really Mn-rich red varieties of epidote. (See for example: Ashley (1984), Kawachi et al. (1983), and Martin & Lombardo (1995).)

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- This locality has map coordinates listed. - This locality has estimated coordinates.ⓘ - Click for further information on this occurrence.? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant.(TL) - Type Locality for a valid mineral species.(FRL) - First Recorded Locality for everything else (eg varieties).Struck out - Mineral was erroneously reported from this locality.Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.